[Viral pneumonias: typical and atypical findings]

The clinical and radiological features of viral pneumonias are summarized and discussed. Although viral infections of the lung belong to atypical pneumonias they do not demonstrate always the radiographic pattern of an interstitial pneumonia. Characteristic radiographic findings are quite rare. In most cases the microbial etiology cannot be predicted from chest radiographs. The appearance varies depending on the virulence of the organism and the resistance of the host. In this regard knowledge of epidemiological data as well as patient condition and underlying disease is of utmost importance. Differentiation between community- and hospital-acquired infections may be very helpful.